Telephone system



Feb 28, 1933.

G. R. EATON ET AL TELEPHONE SYSTEM 3 Sheets- Sheet 1 Filed Sept. 21, 1951 7171.15" 1770 P5: L'ew'gs'fj 55 cm Feb. 28, 1933. R EATON ET AL 1,899,084-

TELEPHONE SYSTEM Filed Sept. 21, 1931 3 Sheets-Sheet 3 W o D m w a} M o &

\Q N N gefiEaYun nnffi'ner to the contacts of the desired line.

Patented Feb. 28, 1933 UNITED STATES v PATENT OFFICE GEORGE E. EATON, 'OF OAK PARK, AND GLENN .ZKIZNER, OF CHICAGO, ILLINOIS, AS-v SIGNORS TO .KELLOGG .SWITCHBOARD & SUPPLYCOMQPANY, OF CHIGAGO, ILLINOIS,

.A CORPORATION OF'ILLINOIS TELEPHONE SYSTEM Application filed September 21,1931. ,Sefialh'c. 563,928.

Our invention relates to automatic telephone systems of the two-wire or metallic line type in which directively' controlled switches at the exchange are operated in response to a series of rapid interruptions of the subscribers"line circuits to connect the calling subscriber thereat .to'the contacts off theline being called. The system which is herein disclosed is applicable to private automatic exchange or FAX systems .as they are commonly known.

WVhen in the usual system of this type, a subscriber removes his receiver to initiate a call, a line finder switch connects his line to a selector whereupon he operates his dialing device to stepvtheswitc'hwipersof the rotary selector switch into engagement with con: tacts leading to a connector which in turn is operated to have its switch wipers connect Itis an object of our invention to provide animproved circuit arrangement using a plurality of 'countingrelayls in {the selector .circuit which eliminates the selector switch and its associated banks of contacts.

A further feature of our invention is the use of a single levelrotary ,switch (shown herein as provided-withfio sets of contacts) in the connector circuit to which the subscribers stations are connected. i 1

Another feature visthe provisionin a .telephone system of the type described ofmeans for driving theswit'ch wipers to a predeterminedpoint and then stepping them into engagement with the desired setof contacts.

Other features will be disclosed from time to time as the description of the invention progresses. v I

1n the accompanying drawings like reference characters indicate likeparts and Fig. 1 is a schematic drawing of: .theapparatus comprising the line finder switch of our invention;

Fig. 2 shows the selector circuit, and

F'g. 3 shows theconnector circuit.

'l Vhen Fig. 2 is 'placedito the right of Fig. 1 and Fig. 3 is placed to the right of-Fig. 2-the entire circuit arrangement will be disclosed.

. The present :invention YVlll-ibG best understood .from a consideration of the following detailed description taken in connection with the accompanying drawings forming apart of this specification, with the understanding, however, that the invention is not confined 'to any strictc'onformity with the showing of the drawings but may be changed or modifiedeso no material departure from the salient fea; tures of the invention as expressed in the ap pended claims; Referring part'icularly to' Fig. 1 of the drawings the. line conductors 1 and 2 at; the

left of the drawing lead to a subscriberssta tion, not shown, which is equipped withthe long as such changes andinodifications. mark 5 er to step the wipers 3, 4, 5 and 6 over the bank contacts 7, 8, 9 and 10 to select the con tacts of the calling line. A bridging relay BG is provided which energizes when the calling line is seized by the switch ES to shunt the motor magnet' to prevent further advancement of the ,v wi'pers 3, 4,5 and 6' and to connect the calling line to the selector mechanism or switch SS. Theisleeve relay SL energizes-upon the actuationof are lay BGr to extend the starting-conductor 11 to thenext finder switch F S not shown) of the group. A release magnetR'E which restores the'wipers 3, 4, 5 and 6 to normal is provided. [A supervisory relay SR supplies talking battery to the snbscribers line and is alternately energized and deene-rgized when the subscriber actuates "his 'dialing mechanism to cause the actuation of the selector SS and connector US. *A busying relay BB is providdto cause :the operation of an associated part of group busying means (not shown) and to startiaetone mac'hineopcrating asis well known in zthevart. If all the finder switches in thegroun' with which the callingsubscriber isiassociatedare busy agronp busy, tone will be-,given.;the .sub-

scriber as soon as the line relay LRcloses its alternate,v contact. 31 and connects "the conductor c, to line 1.;The relay BB in. each finder switch ofthe group operates to condition apparatus to l connect agroup busy tone to the conductor when all the finder I switches are busy.

The selectorswitch SS is devoid of rotary switch and bank contactsas are .cus-

I switch CS.

switching relay SW which extendsthe dialconductor DC wa connector switch I in 0% are alsoprovided.

.? The connector switch CS shown is of a construction substantiallysimilarto. that'ofthe finder switch FS and comprises i a shaft which carries the wipers 13, 14', 15

V and 1 6 whichareiadapted to, be stepped into engagement with the bank contact's 17, 18, 19 and 20'through' .the mediunilof a motor magnet MM." A release magnet RE is also providedwhich whenlactuated releases the the desired contact I switch wipers 13,-12t,15 and 16andrestores subscribers lines; 7 v t f The present embodiment of our nvention them' to normal; The contacts 17,18 and 20 which are the tip, sleeve and. ring conassociated with the called subs-cribers stations, not shown in the drawings but similar to the line circuit L of Fig. 1 associated with the'calling subscribers line, and lead to called utilizes a fifty'point-switch which" allows an exchange 'to consist of fifty single lines; However, it is readily apparent that a larger switchco'uld be used to enlarge the exchange to the desired number of subscribers. If a larger switch is used itwill benecessary to add one more countingrelay in the selector switch for each ten lines added as will be apparent from the ensuing specification As'it is necessary'to dial twice to cause the proper functioning of the selector and connectorswitches the first line inthe group will be arbitrarily designated number 11,,the

second number 12, and soon to the first tenth? contact which leads to line number 10. The contact after line number 10 will be number 21 and then number 22 and so forth to the'second tenth contactwhich is associated with line number'20. Thenext line is line number-31 and the contact after line numberBO Willbeline number 41. The

nextto the rlast contactis number 59 while the lastcontact is number 50. It will thus be seenthat "provision is made for fift'ysub- An off normal relav OF and a.

local contact, is adapted to be grounded by contacts of one of the impulse or counting relays when the relays are operated under control of the substation sendingv device. When the relay B operates it closes its contact 21 to ground the contact 19 by means of conductor 22; When relay G operates alterconductor 28 and the fifth.tenth contact 7 In the system of our invention the brushes of the connector switch CS are driven to the tenth contact lower than the contact leading to the called subscribers line and then stepped under directcontrol of the substation sending device into engagement with the desired set of contacts. Upon the first dialing movement thecounting relays. A, B, C,

etc. operate insequence to ground the tenth 'contact selected and drive the connector switch US to this contact where it will come to rest; Upon the second dialing movement the connector switch CS is stepped one point for each interruption of the line conductors 1 and-2 and. after the last interruption reaches For instance, if the number of the called party is 35 the calling subscriber will dial 3 in the vusual manner. which. will interrupt the line conductors three times and cause the operation ofrelays A, 'Band ,Ci which will ground contact 19 which is the second ftenth contact and leadstothesubscribers f station whose number is twenty.; The magnet MM will drive the wipers 13,14, 15mm 16 to the sacraments in which grounded contact 19 islocated where they will stop. The calling subscriber will next dial the five and the motor magnet lWM' 'will step the wipers to the. fifth set of contacts after19" which fcontactslead to the line number 3.5.

The connector switch circuit is also provided with a'ringing trip relay and a ringing cutolfrelay RCO which operate .supplies talking battery current to his line.

whenthe called party responds to disconnect A busy tone relay BTR is provided and operates when the called line is busy to supply a distinctive busy tone to the calling subscribers line. :A secret service relay SS,'a

1 guard relay GU, an interrupter relay IR and switching relays SW? and'SW? Man supestablishing ifferent connections.

* Assuming. maths 'subsc-riber whose line terminates in Fig. 1 desires to converse with another subscriber at the private branch exchange, he will remove his-receiver from its switchhook which establishes an energizing circuit for the line relay LR of line circuit L. This circuit may be traced from battery, through the upper winding of relay LR, normal contact 32 of relay CO, conductor 2, through. the closed switchhook contacts at the calling subscribers station (not shown) back over conductor 1, normal contact 33, of relay CO, and through the lower Winding of relay LR to ground. The line relay LRenergizes and closes its alternate contacts 29, 30 and 31. The closure of contact 29 grounds the conductor 11 and causes the motor magnet Mh/I to operate to step the wipers 3, 4, 5-and 6 into engagement with the first set of contacts 7 8, 9 and 10. The energizing circuit of motor magnet MMmay be traced from battery, resistance R, motor magnet MM, nor mal closed contact 34, normal closed contact 36 of the off normal springs ON, conductor 37 normally closed contact 38, of sleeve relay SL, conductor 11, to ground at alternatecontact 29 of relay LR. The circuit of the motor magnet Mh/l is opened up on the first step of the wipers 3, 4, 5 and 6 due to the opening of contact 36, of the OE normal springs ON which assume their alternate positlon upon the first movement of the wipers 3, 4, 5 and 6. The closure of alternate con- V tact 56 of ON establishes aniillumina'ting circuit for an OK normal pilot (not shown) through the punching p. This off normal pilot-lamp remains illuminated during the time the switch is hunting the calling line and if the switch does not find the line the lamp will indicate which switch is giving the trouble. 1 I

A substitute circuit for the motor magnet MM is established if the first set of contacts 7 8, 9 and 10' are not the contacts of the line of the calling subscriber. This circuitmay be traced from battery, resistance R, motor magnet MM, closed contact 34,'al-

ternate contact 39, of the off normal springs ON, conductor 40, normal contact 41, conductor 42 to ground at normal closed contact 32 of the bridging relay BG. The contact 34 of the motor magnet MM is moved to its alternate position upon the energization of the motor magnet MM and thus opens the energizing circuit of the same which immediatelyreleases its armature and again closesthe contact 34 to establish another energizing circuit for the magnetlllM to stepthe wipers 3, 4,; 5 and 6 into engagement with the next set of contacts. The alternate opening and closing of the contact34 causes the wipers to he stepped over the contacts 7, 8, 9 and 10 in search of the contacts of they calling line. Condenser w is bridged across the motor magnet MM to prevent sparking during the rapid opening and closing of the contact 31.

The instant wiper 5 engages the contact 9 associated with the callingline, a shunt circuit for the motor magnet MM' is established which prevents the further operation of the motor magnet andthe wipers remain in. engagement withcontacts 7', 8, 9 and 10 of the calling line. This shunt circuit which is also an energizing circuit for the bridging relay BG may be traced from battery through resistanceR, lower winding of the relay. BG, conductor 44-,normal closed'contact 45 of the relay BR, conductor 46, normal closed contact47 of the sleeve relay SL, wiper 15,contact 9, to ground at alternate contact. 30 of relay LR.

Upon energizing, bridging relay BG also opens the circuit of the moto-rmagn et MM at its contact 43 and establishes an energizing circuit for the sleeve relaySL and the cut off relay CO. which circuit may be traced from battery, through the upper winding of relay SL,,conductor 48, alternate closed contact 49 of relay BG, conductor 50, wiper 4, contact 8, conductor 51, through the winding of relay CO to ground. The cut off relay OO energizes and-opens its contacts 32an'd' 331to deenergize relay LR which removes ground from contact 9: and starting conductor-11. The removal of ground from contact 9 allows the wipers of another finder switch ofthe group to pass over the line of thiscallingsubscriber' shouldanother finder switch of the group be operated during the present connection;

The heavily marked talking conductors TO and TC are closed at'a'lternate-contacts 52 and 53 of the bridging relay BG tocomplete the talking circuit through to the connector switch. The closing of contact 54 of the relay SL opens the circuit of the oil normal pilot lamp and also establishes a locking circuit for the said relay which may be traced from battery through the lower winding of the relay SL, alternate contact 54, conductor 55, to

ground at alternate contact 56 of the off normal springs ON. This circuit maintains the sleeve relay SL in its energized position until the otinormal springs ON arerestored to normal which restoration *does not -take place until the wipers 3, 4, 5 and 6 have been re stored to their normal position by the operation of the release relayRE. The conductor 11 is' a common starting conductor andis associated with the contact 29 of all the relays LR of the group. Upon the energization of relay SL its contact 38 assumes its alternate position to extend the'common starting conductor 11 through to the next finder switchof the group by way of punching p.

Upon the closure of alternate contacts '52 and 53 of BG an energizing circuit is estab 7 lished for the supervisory relay SR which circuit may be traced from battery'lthrough I the lower winding of relay SR, conductor 57,

alternate contact 53 of relay BG,'wiper 6, and

contact 10, over the subscribers linean'd back 1 tact'52 BG,'c ontact 58, through theupper Winding. otrelayYSR to ground. -Relay SR energizes and closes its alternate contact:59

which estahlishes'an energizing circuit for 'busying relay BR. 7 This circuit may be traced from battery, through the relay; BR, to

ground at alternate contact 59' of relay SE. The opening ofcontact if of relay SL interruptedthe original'energizing circuitof the bridging relay BG but'as the relay BG is slow torelease a substitute circuit is closed through alternate make-before-break contact 60 of relay BR, and the bridging relay BG is maintained energized by current fiowing from battery, throughfresistance R, lower. winding of relay BG, conductor 44, make-before-break contact 60 and upper winding of'BG to ground...

The closingof alternate contact 61 of relay BResta'blishes a starting circuit for a ringing tone machine (notj shown) which supplies ringingzcurrent, a dialing tone, abusy tone and a group busy tone. The closing of alteri nate contact 62 of relay BR conditions'ap- 'paratus in a group busyingcircuit (not shown) over conductors 63 and 64.

v Assoon as'the relay BG operates toconnect I the finder switch FS to the selector switch SS thecalling' subscriber will receive a dialing tone which informsthelsubscriber that the dialing maybe started. This dialing tone'circuit may be traced from conductor 65 which leads to. the ringing tone machine, normal contact 6601 off normal relay OFR'ot the selector circuit, conductor o7, normal contact 68 of the'otlnormal sprlngs ON, normal contact 69 of relay RCO,'conductor 70, over the heavily, marked talking conductor TC, alternate contact 53 of relay BG, wiper 6, con-- tact 10, conductor 1 to the subscribers receiver. Upon receiving this signal the calling subscriber-willknow that the apparatus is in condition'for the dialin g operation.

, Assuming that the called subscribers number is:, l5",' the calling subscriber. will first dial the number land thereby interrupt the tall'ringc-onductors four times in the usual,

manner. Upon the first interruption of the talking conductors the supervisory. relay SR will restore to normal and close its normal contact 59, The relay BR will remain in its operatedpositiondue to the copper slugs -whichmake it slow acting, thus grounding the dialing conductor DC and closing the energizing circuits torthe switching relay SW,

' the secret dialing relay SDR and the first counting or impulse-relay A. The circuitfor the switching relay SW may be traced from gm battery throup'h' the winding 'of the relay SW, normal contact 93' of SW, to the conductor DC; the one for the secretdialing re lay .SDR from batterythrough the winding of the relay SDRto the dialing conductor 'DC;and the circuit for the relay A. from battery through the relay A, normally closed contact 71 of relay A, normal contacts-71 71, 71% 71", conductor 72, normal contact 7 3 .dialing conductoris, connected to ground at normal contact 59 of relay SR, through alternate contact 74 ofrelay BR. Switching relay SW will open its .normally'closed con 7 tact 7 5 to prevent switching relay SW from counting relays. This'timing of the impulse .of SDR, to the dialing conductor,:which assures the desired operation of the relay A. Relay- A energizes'and'attracts its' contacts 76 to close the energizing circuit for-the ofi normal relay OFR which may betraced from a battery through the upper winding of the're- I lay ()FR. alternate contact'l'tiflf'normal contacts 76 76 7'6 and 7 (S -of the relays B, C,-:

i D and E, conductor 7 7 to'g round at alternate contact 4320f bridging relay BGQF The otf normal relaycloses a lockingcircuit for itselfthrough its alternate contact 78 and attracts its contact 66 to disconnect the dialing tone from the talking conductors;

, Uponthe next interruption of the talking conductors the-relay SR again d-eenergizes and restores its contact 59 to normal thereby again placing ground upon the dialing conductor'DG and closing a circuit for the relay SDR which again regulates the length of the impulse to the second impulse relay B which circuit may betraced from battery through the winding ofthe relay B, alternate'contact 71 or relay A, to ground at normal contact 59 over the'previously-de scribed path. The .relayB attractsits'armav:

ture 76? to open the energizingv circuit of the relay A which rest-ores to normal." The j relay B also closes its alternate contact 21 thereby furnishing ground. to'contact -19 as above explained; It also attracts its contact 81 to furnish ground to the motor magnet MM of the'connector switch CSiwhich ,op-

:erates over the following 'circuitfbattery,

through the windingotthe motor ma'gnet MM, conduc-tor'83, normal contact 84,0f i

SW normally closed contact of normal contact86 of 7 IR, conductor 82 a to ground at 81 of the relay B1 The motor magnet MM operatesto step the'wipers 13, 14:, 15 and 16 to thefirst set of contacts 17,. 18, 19 and 20 and also opens its contact 85 which interrupts the energizing circuit for tact 85 to form. another energizing circuit .the motor magnet MMfwhich accordingly. restores to normal-andzagain closes its confor itself. Each time the motor magnet MM is energized it steps the wipers of the switch to the next set of contacts as explained in connection with the motor magnet MM of the finder switch FS.

Upon the third interruption of the talking conductors a circuit is provided for a third impulse relay C which circuit may be traced from battery, through the winding of the relay C, alternate contact 71 of relay B to ground at normal contact 59 of the relay SR. The attraction of the armature 7 6 opensthe energizing circuit of the relay B which restores to normal and opens its contact 21 to remove ground from the contact 19 and restores its contact 81 to remove ground from the circuit of the motor magnet MM; However, the contact 81 of relay C closes before the contact 81 opens to supply-ground to the circuit of themotor magnet MM" which continues to operate; The closing of alternate contact 23 of relay C grounds the contact 19 Each of the relays A, B, C, etc. establishes a locking circuit for itself'through its alternate contact 76*, 76 76, etc. and conductor 77 to ground at alternate contact 43 of BG. However, each relay A, B, C, D, and E opens the locking circuit for the previous relay so that all except the last relay to operate restore to normal. I

Upon the fourth interruption of the talking conductor the relay D operates over a cir cuit traced from battery through the winding of the relay D, alternate contact 71 of the relay C, to ground at normal contact 59 ofthe relay SR. The relay D closes its alternate contact 25 to supply ground to the contact 19 and opens its contact 7 6 to open the circuit "for the relayC which deenergizes and restores its" contact 23 which disconnects ground from the contact 19 and also restores its contact 81 whichdisconnects ground from the conductor 82 leading 'to the motor magnet MM. The closing of contact 81 of relay D suppliesground to the'motor magnet M'M' which continues to operate over the previously described circuit. As we have assumed that the number of thecalled party is 4.5 this fourth interruption is the lastone and the locking circuit for the relay D will be closed which circuit may be traced from battery through the winding of the relay D, alternate contact 7 6 normal contact76 and conductor 77 to groundat alternate contact 43 of BG. v v

As soon as the dialing is discontinued the energizing circuit of the relay SW is opened at contact 59 of SR and SW deenergizesand restores its contact 7 to normal thereby closing' an energizing circuit for the switching relay SW. The circuit may be'traced from battery through the winding of the relay SW, normal contact 75, alternate contact79 oi OFR, conductor 77 to ground at alternate contact 43 of BGL The relay SW closes a locking circuit for itself through its. alternate contact 92-. The motor magnet MM" continues to operate until the wiper reaches magnet MM and stops the movementof the wipers 13, 14;, 15 and 16. The closing-of alternate contact 87 of the relay IR closes an initial energizing circuit for the switching relay SW which may be traced from battery through the winding of SW alternate-contact 87, conductor 88, normal contact '89" of relay'A, conductor 90,. alternate contact 91 of SW, conductor 77, to ground at alternate contact 43 of BG. The relay SW? energizes over this circuit and closes a locking circuit for itself which maybe traced frombattery through the winding of SW alternate con-' tact 108, conductor 120, conductorlv77fito ground at alternate contact 13. of relay BG. Tens operation of the connector switch in reality consists merely in an automatichunting for a tens contact which has 'been grounded by a selected counting relay A, B

The step by step operation of the connector switch is so rapld' that by thetime the last tens impulse has been registered the brushes 7 of the connectorflswitch aretraVrsingthe final group of'tens contacts so'that the tens selection is completed beforethe dial can possibly be operated to send 'the'unit-s impulsesf I Y Y V The subscriber next dials the digit 5 and thereby causes the energizing circuit of the relay" SR togbe interrupted 5 times. Upon the first interruption'the r'elay'SR restores its contact 59 to normal thereby closing the'energizingscircuit for the 'motormagnet- MM which may be traced from-battery through also operates over this circuit'and closes'its alternate contact 98 thereby establishing an energizing circuit for the switching relay SW3 which may. be traced from battery through the winding of SW conductor: 99,

relay RCO to ground. The relay GU'op'ens its contact 102 to interrupt the energizing circuit for the secret service relay SS and the cut off relay CO which restore and place the contacts of the called subscribers line in.

ing all the apparatus in its normal condition ready for a new call.

It the called subscriber does not answer when the ringingcurrent is applied to the line, the calling subscriber, after waiting a reasonable length of time. replaces his receiver to cause the restoration of the apparatus in the following manner; the relays SR. BR and BG restore as before explained and the restoration of normal contact 126 of 13G closes an energizing circuitfor the ringin cut-oft relay RCO which circuit may be traced from battery through the upper winding of the relay RCO. alternate'contact 127 of cit-normal springs ()Nflcondu tor 128. to ground at normal contact 126 of relay BG. I closes its alternate contact'f)? to, form an energizing circuit for the release magnet RE a d guarc relay GU as traced previously. The switches 13. 14. 15 and 16 are restored to normalunder the influence of the re ease magnet RE as before explained.

If the called line is busy the'operation ot' the apparatus will be the same up to the poi t where the swit hes 13:14. .5 and .0 enea ic the contacts 17. 18. 19 and 20 of the called line. lf'the called line is busy as a called line the secret service relay S3 of another connector switch CSwill have onerated in series with the cut-off relav of the line circuit of the called subscriber and closed its alternate contact to shunt resistance R in the. other switch CS. There fore. when the contacts 13. '14. 15 and 16 of this connector switch engage the contacts of the calledline the secret service relay SS of this connector will not operate due to the inclusion of the resistance R in the circuits. The busy test relay BTB will operate by current flowing from battery through the husv test relay BTR, normal contact 100 of SS, conductor 101, normal contact 102 of GU, conductor 103, alternate contact 1040f Sl/V conductor 105, wiper 14, contact 18 to ground through the cut-off relay. The busy test relay BTR closes its alternate contact 108 to linecircuit of the called subscriber.

The relay RCO energizes and.

connect distinctive busytone to the calling subscribers receiver. This tone may be traced from'conductor 129, which leads to. the ringing tone machine previously mentioned, alternate contact 108 of BTR, conductors 109 and 110 to the calling subscribers station over the heavily vmarked talking conductors. The calling subscriber will recognize this tone and replace his receiverto restore the apparatus to normal in the previously described manner. Therela-y BTR also opens itscontacti 95 which prevents the operation of the motor magnet MMywhen the suhscriberfhangs up. If contact95 was not opened the restorationof 59 of SR would 7 cause the energization of MM andthestepping of the wipers to the next set of contacts.

If the called line is busy as a calling line the sleeve relay SL of another finder switch FG will be energized: through the winding of the cut ofi' relay CO associated with'the The secret service relay SS of the connector switch CS shown in the drawings; will not operate because of the resistance cf but-th'e'busy testrelay-BTR will operate to;v connect the busy tone signal to the calling subscribers receiver. g r g g If the contacts otthe called subscriber are within the first ten, "which'contacts are associated with lines numbers 10 to 19inclusive,

the operation of the finder switchwill be the same as previously'described. The calling subscriber will dial 1 as the first digit of the called partys number which will cause the operation of the switching relay SW, the

secret dialing relay SDR and impulse relay A and relay OFR, all as before described.

. ,The relay A remains energized, after contact 59-of SR has been again attracted, through its locking circuit which may be traced from battery through the winding ot relayA, al-

ternate contact 7 6*, normal contacts" 76', 7 6,

76 and 7 6 and conductor 77, to ground at alternate contact 48 of relay BG, The relay A closes an energizing circuit at its alternate contact 89 for the switching relay SW which circuit may be traced from. battery'through the switching relay SW conductor 121,"alternate contact 89 of A, conductor 90, alteia nate contact 91 of SlV, which has also energized, conductor 77 to ground. at alternate contact 4301: relay B6}. The switching relay SW operates to attract its contact 84 to connect the motor magnet MM to dialing conductor DC. It will be] noted that the cuit of the supervisory relay SR four times and connect ground tothe dialling conductors DC and DC four times to cause the motor magnet MM to operate "and step. the wipers13, 14,115 and 16 to the I first dial 2 which willinterrupt the talking fourth set of contacts which lead to the line of thedesired party. The operationot the apparatus from then on is the same as in the previously traced connection.

Assuming that the number of the called party is number 20, the subscriber will conductors twice.- .The" first interruption causes the operation of the relay A and the-second interruption causes the operation of-the relay B whichcloses its'alternate contact 21' to ground the contact 19 whichis the first tenth contact in the bank The motor magnet MM willbe caused to operate due =tofthe closure ofalternatecontact' 81? to drive the wipers untilthey reach the con tact 19* at whifch point they-will stopdue to the energization of the interrupter relay IR "as explained in the previous circuit contacts which will be line number 20. Thecon versational circuit-is then established asde-f scribed hereinbefore.

" Obviously, the invention is susceptible of 4 80 embodiment informs other than that which is illustrated" in the accompanying drawings and:describedherein, such, forinstance, as

thesuh'stitution of-a s witch for the counting V I StatesLetters Patent is: r -,-1..'A telephone system including'a plua .zsog imhm desired contact.

relays to progressiv'elyground the tenth contacts .o'f'the connector switch, and we therefore consider as our own all such modifications and adaptations of the form of the invention herein described as'fairly fall with in the scope of our invention. 1 "f Having described our 'invention'what we claim is new and desire'to secure by United ralit-y-of subscribers stations, a linlrcircuit for interconnecting certain o-fsaid" stations,

a.sW1tch,'a plurality of contacts and means n relays responsive to sa1d dialing means for including a group of counting relays for altering the potential'of a predetermined con- 2.'Astelepho ne system including a plurality of subscribers" stations, a link circuit for interconnecting certain of said I stations,

a switch, a plurality of contacts, and means including a group 'oficounting relays adapted v to alter the/potential of certain predet er mined contacts andlto drive said switch to telephone system including a plu rality of subscribers stat ons, a link circuit for interconnecting certainof said stations,

aswitch, a plurality'of contacts, m-eans in- I 'clu'dinga group-of counting relaysiadapted' "tofalter, the :potential' of certain predeten mined'contac ts and to drive said switch and to stop said switch on one of saidpredeterminedcontacts. I 4. A telephone system includlng a pluraln tyof subscribers" stations, a link circuit for interconnecting certain of said stations, a

switch, a plurality of contacts, actuating.

means for said switch and means including a group of counting relays adapted to alter the potential of certain of said contacts and stop 5. A telephone system including a pluralilays adapted to respectively alterthe potenv an of certain of said contacts and thereby controlling the operating means of said switch.

terconnectingv certain of said stations, a plurality of sets of contactseach associated with a subscribers station, switch wipers asse ciated with sa1d sets of contacts, operating means for said wipers, a group of. counting relays controlling the potential of a predetermined contact to drive said wipers to said predetermined contactfand means for-stepping said wipers intogengagement with the contacts of a desired subserlbers station.

7. A telephone system including 'a plu- ;rality of subscribersstations, means including' a group of counting relays for interconnecting any two of sa1d stations, dialing I v l 6. A telephone system including a plurality of subscribers stations,-means forinmeans at said subscribers stations and a group of counting, relays responsive to said dialing meansfor altering the potential of certaingof'said contacts.

8. A telephone system including a plurality of subscribers stations, means including a plurality of contacts for interconnect ing anytwo of said stations, dialingmeans at sa1d subscrlbers stations, a group of countaltering the potential of certain of'said contacts and} a switch controlled by said group of counting relays.

9. A telephone system includinga plurality of subscribers stations, means includinga plurality of'contacts forinterconnecting any 7 two of said stations, impulse imparting means at said subscribersstations, a group of count- 1ng relays foraltering the potential of certain of said contacts, each-succeeding relay being 10. A telephone system including a plural:

of subscribers lines, contacts 'forcach of said lines arrangedin groups, a switch adapted to engage sa1d contacts, operating means 'for said switch, a group' of counting relays controlling the potential 'ofione c ontact in 7 each group and controlling said switch opresponsive to-each succeeding impulse of said impulse lmpartlng means.

said. switch on said certain contact. r

crating means to drive said switch to a predetermined group of contacts.

11. A telephone system including a plurality of subscribers lines, contacts for each of said lines arranged in groups, a switch adapted to engage said contacts, operating means for said switch, a group of counting relays controlling the potential of one contact in each group and controlling said switch operating means to drive said switch to a predetermined group of contacts and means associated with said counting relays to stop said switch at said predetermined group of contacts.

12. A telephone system including a plurality of subscribers lines, contacts for each of said lines arranged in groups, a switch adapted to engage said contacts, operating means for said switch, a group of counting relays controlling the potential of one contact in each group and controlling said switch operating means to drive said switch to a predetermined group of contacts and other means adapted to step said switch into engagement with the contacts of a desired line. v

18. A telephone system including a calling subscribers line and a called subs cribers line, contacts associated with each of said lines, a switch associated with said contacts, operating means for said switch, dialing means and a group of counting relays responsive to said dialing means controlling the potential of certain of said contacts and thereby controlling said switch operating means.

14 in an automatic telephone system, an impulse sending device, an automatic switch, contacts for said switch divided into groups, certain of said contacts designating the groups, respectively, means operated under the control of said sending device for altering the potential of a desired group contact, and means for causing said switch to automatically hunt for said altered contact.

15. In an automatic telephone system, an impulse sending device, an automatic switch, a brush for said switch, contacts for said switch divided into groups, certain of said contacts designating the groups, respectively, means operated under the control of said sending device for altering the potential of a desired group contact, a stepping magnet and controlling means therefor for causing said brush to automatically hunt for said altered contact.

16. In an automaticitelephone system, an impulse sending device, an automatic switch, contacts for said switch divided into groups, certain of said contacts designating the groups, respectively, means operated under the control of said sending device for altering the potential of a desired group contact, and means for causing said switch to simultaneously automatically hunt for said altered contact.

ti-vely', 'a seriesof counting relays operated 1 under the-control of said sending. device for altering the potential of a desired group contact, a stepping magn-et and controlling means therefor forccausing said brush to automatically hunt for said altered contact. 18. In an automatic telephone system, an impulse sending device, an automatic switch, a brush, for said switch, contacts for said switch divided into groups, certain of said contacts designating the groups respectively, means operated under the control of said sending device for altering the potential of a desired group contact, a stepping magnet and controlling means therefor for automati-v cally moving said brush over said contacts, and means for interrupting the movement of said brush incident to engagement with a contact having altered potential thereon.

19. In an automatic telephone system, an"

impulse sending device, an automatic switch, a brush for said switch, contacts for said switch divided into groups, certain of said contacts designating the groups respectively, means operated under the control of said sending device for altering the potential of a desired group contact, a stepping magnet and controlling means therefor for automatically moving said brush step by step over said contacts, and means for interrupting the movement of said brushincident to engagement with a contact having altered potential thereon.

20. In an automatic telephone system, an

impulse sending device, an automatic switch,

a brush for said switch movable in a single plane, contacts for. said switch divided into groups, certain of said contacts designatin the groups, respectively, means operate under the control of said sending device for altering the potential of a desired group contact, a stepping magnet and controlling means for simultaneously automatically moving said brush step by step over said contacts, and means for interrupting the movement of said brush incident to engagement with a contact having altered potential thereon.

21. In an automatic telephone system, a

substation, an impulse sending device there at, an automatic switch, a brush'for said switch movable in a single plane, contacts for said switch divided 'into groups, certain of said contacts designatingthe groups respectively, a series of counting relaysoperated under the control of said sending device for altering'the potential ofa desired groupcontact, a stepping magnet and conf 'S trolling means" thereferyfbi" simultaneoiisly automatica11y moving said brush 'step by 7 step over said Contacts, and'means for interrupting the movementof said brush incident 5 to engagement with a contact-having altered potentiali'thereon.

Signed by us, at Chicag0,-in the county of Cook and State of lllihois this 17th day of September,. 1931. V e GEORGE R. EATON.

V, GLENN KINER. 

